DozeClock › Sounds › Brown noise
Brown noise for sleep: what it is and what the research says
Updated October 27, 2026 · measured from the app's files · Sources: Messineo 2017 · Papalambros 2017 · Riedy 2021 · Wikipedia (CC BY-SA)
Short answer
-6 dB
per octave: energy falls fast with frequency; a low rumble (distant surf, a waterfall, an aircraft cabin). Of the app's 30 recordings, the closest measured is sea breeze (−6.7 dB per octave). Evidence for sleep: small studies, low-quality overall — useful for masking, not a treatment. Play it below with a sleep timer.
General information from population studies (NIH, CDC, NSF, AASM). It is not medical advice and does not replace a clinician who knows you.
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Brown noise, a low rumble
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In the app each room layers its own sounds (rain on the roof with distant thunder, waves with a sea breeze), each at its own volume. Free gives you the Rain and Beach rooms with 3 sounds each and plays while the app is open; Plus adds all 30 sounds, saved mixes and play with the screen locked, on iPhone and iPad. A browser tab can also stop when your phone locks. Free vs Plus →
White 0 · pink −3 · brown −6 dB per octave — definitions adapted from Wikipedia "Colors of noise", CC BY-SA 4.0 · as of October 3, 2026
Brown noise measured: a reference file and the nearest sounds in the app
Our generated reference brown noise measures −5.3 dB per octave, a little brighter than the textbook −6 because the file keeps some energy above 2 kHz. Of the 30 recorded nature sounds in the app, the closest to brown noise are Sea breeze (−6.7), Distant thunder (−6.8), Crackling fire (−4.9).
| Sound | Closest colour | Slope (dB/octave) | Energy centre | Loudness swing | Loudest moment |
|---|---|---|---|---|---|
| Brown noise | brown | −5.3 | 240 Hz | 0.2 LU · steady | +0.6 dB |
| Sea breeze | brown | −6.7 | 190 Hz | 2.9 LU · steady | +2.4 dB |
| Distant thunder | brown | −6.8 | 80 Hz | 7.1 LU · gently varying | +7.1 dB |
| Crackling fire | brown | −4.9 | 180 Hz | 3.8 LU · gently varying | +6.5 dB |
| Creaking wood | brown | −4.9 | 300 Hz | 7.3 LU · gently varying | +7.3 dB |
Measured by DozeClock from the app's own audio files (AAC, 48 kHz): spectral slope = straight-line fit of octave-band levels from 63 Hz to 8 kHz, converted to dB per octave per hertz (white 0 · pink −3 · brown −6); loudness swing = EBU R128 loudness range (LU); loudest moment = highest 400 ms loudness above the file's average (dB). Checked against reference white, pink and brown noise we generated (made for the app's next version, not in the current App Store version), which measure +0.1, −2.8 and −5.3. Measured October 27, 2026. Recordings: Freesound, CC0 (linked), as shipped in the app; noise rows are reference files we generated. Full table for all 36 sounds and a CSV: open data.
What brown noise actually is
Brown noise energy falls fast with frequency; a low rumble (distant surf, a waterfall, an aircraft cabin). In engineering terms its spectrum falls 6 dB for every doubling of frequency, which is why it sounds deep, like distant surf. The other two colors are shown faintly on the chart for comparison.
What the research shows
Brown noise has almost no sleep research of its own — most studies use white or pink noise. Its appeal is practical: the low rumble masks traffic and voices without the hiss of white noise, which some people find harsh. The 2021 systematic review (Riedy) covers continuous noise in general and rates the evidence as low quality; treat brown noise as a comfort choice rather than a proven aid.
How to use it tonight
Keep the level low — enough to blur a passing car, not enough to notice. Most people do better with a sleep timer than with sound running all night: once asleep, a change in sound later can wake you, and the research on all-night noise is mixed. If brown noise feels harsh, try the underwater or fire recordings, which measure at or below brown (table above).
Sources
- Colors of noise — Wikipedia (CC BY-SA 4.0)
- Broadband Sound Administration Improves Sleep Onset Latency in Healthy Subjects in a Model of Sleep Onset Insomnia — Frontiers in Neurology 8:718, 2017 (Messineo L. et al.)
- Acoustic Enhancement of Sleep Slow Oscillations and Concomitant Memory Improvement in Older Adults — Frontiers in Human Neuroscience 11:109, 2017 (Papalambros N.A. et al.)
- Noise as a sleep aid: A systematic review — Sleep Medicine Reviews 55:101385, 2021 (Riedy S.M. et al.)
General information from population studies (NIH, CDC, NSF, AASM). It is not medical advice and does not replace a clinician who knows you.